Instrument capsule for control of a submarine petroleum installation

ABSTRACT

A fluid proof container houses a number of Bourdon tube pressure gauges which govern the fluid pressure of a control fluid for setting the flow rates of various fluid conduits. A bleed line removes a portion of the gas in the controlled fluid conduits. The gas is passed through a series of heating, pressure reduction and drying to eventually supply both the inert atmosphere in the container and serve as the control fluid.

0 United States Patent 1 3,653,398 Orieux [451 Apr. 4, 1972 s41 INSTRUMENT CAPSULE FOR [56] References Cited PETROLEUM INSTALLATION 1,744,872 1/1930 Earl ..137/9 [72] Inventor: Pierre P. Orieux, Paris, France 3,447,552 6/1969 Grosson.. ..l37/8l 3,470,896 l0/l969 Werter 137/1 15 X I A5s1gnee= magma Fmncm Des P 2,074,883 3/1937 Ziebolz etal. ..137/3 France 2,094,192 9/1937 Schmidt.. ..|37/3 o 9 Newton l X [21] Appl. No.: 864,997 Primary Examiner-Samuel Scott Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [30] Foreign Application Priority Data [57] ABSTRACT Oct. 9, 1968 France ..l69240 A fluid p f container houses a number f Bourdon tube pressure gauges which govern the fluid pressure of a control [52] U.S.Cl r ..l37/334 fluid for setting the flow rates of various fluid conduits. A [51] Int. Cl ..Fl6k 49/00 bleed line removes a portion of the gas in the controlled fluid [58] Field of Search ..137/98, 115, 118 conduits. The gas is passed through a series of heating, pressure reduction and drying to eventually supply both the inert atmosphere in the container and serve as the control fluid.

9 Claims, 3 Drawing Figures Patented April 4, 1972 3,@53,398

2 Sheets-Sheet l 2 Sha ia-Sheet 2 Mented April 4, 1972 v tenance of a constant internal INSTRUMENT CAPSULE FOR CONTROL OF A SUBMARINE PETROLEUM INSTALLATION BACKGROUND OF THE INVENTION This invention relates to a capsule involving a series of measurement instruments and especially pressure sensitive gauges intended for the control of the operation of a submarine installation.

By way of example, the capsule involved in this invention may be applied especially for the control of an oil and gas separation-unit in a submarine petroleum installation.

DESCRIPTION OF THE PRIOR ART There are already many submarine petroleum oil wells in operation today, but the crude product produced from these wells must be collected directly by appropriate conduits in surface installations rather than in a submarine separation unit.

A number of factors have interfered with the installation of a submarine separation unit. The main factor being the need for building an installation at a relatively low cost, where the control instruments of the oil-gas separator, which processes thecrude product, could be easily controlled and maintained even at a very great depth.

The present invention includes, in one and the same capsule, instruments used for the control of the installation so as to be able to move them back up to the surface for maintenance.

This invention further relates to a capsule of this type where the power controlling the control valves for the various devices of the installation is taken from the pressures of the various fluids in the installation.

Another object of the invention is to make an instrument capsule where the operation of the measurement and control instruments is independent of the hydrostatic pressure prevailing outside the capsule; this is accomplished by the mainpressure which is equal to or greater than the hydrostatic pressure.

Another object of the invention is to preserve the various instruments from any contact with the marine environment and to prevent the risks of corroding the measurement and control instruments through the permanent elimination of humidity with the help of heat exchanges between fluids used for the transmission of orders to the control apparatuses and the outside environment.

Other advantages and features of this invention will emerge from the following specifications, with reference to the attached drawing which shows, by way of example, a capsule for the oil and gas separator of a submarine installation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a schematic plan view of the submarine installation.

FIG. 2 shows the general diagram of all of the instruments in the capsule controlling the various valves of the installation.

FIG. 3 is a schematic representation of a pressure measurement and control instrument.

FIG. 4 is a schematic drawing of the differential pressure control instrument.

DESCRIPTION OF The PREFERRED EMBODIMENT In the schematic drawing in FIG. 1, the instrument capsule, which is the object of this invention, is shown by assembly 1, while the crude oil separator tank is shown by assembly 2.

The crude, coming from the submarine petroleum drill hole, is directed by conduit 3 toward capsule 1. After control of the input flow rate, the crude is directed, via conduit 4, toward separator 2, the crude separating into a gas and an oil. The gas thus separated is directed through conduit 5 toward instrument capsule 1 Which'controls the flow rate of the output conduit 6. The oil from separator 2 is likewise conducted by conduit 7 toward capsule 1 and after control of its flow rate, through outlet conduit 8.

Referring now to FIG. 2, the capsule 1 comprises a tight casing 9 which contains various control instruments, and uses as a control fluid the gas, under pressure, coming out of the separator and arriving at the capsule through conduit 5.

A portion of the gas is diverted from conduit 5 through a conduit 10 containing a valve 1 l. The gas is directed toward a heat exchanger 12 which is outside the tight casing 9. In order to prevent any corrosion of tube 10 by ocean water, the heat exchanger consists of a casing 13 which cannot be corroded by ocean water and which contains a heat exchange coil, in series with tube 10. The heat exchanger 12 can incorporate any additional conducting medium to facilitate the rapid exchange of temperature between the surrounding environment and the gas circulating in the coil.

The temperature drop resulting from the passage into the exchanger 12 brings about a rather considerable condensation of water vapor contained in the gas. The mixture of gas and water is then moved on toward the lower portion 14 of a desiccator 15; The separated water flows through conduit 16 to the outside of the capsule, while the gas coilected at the top of the apparatus, in conduit 17, is dried by the desiccator.

The gas coming from conduit 17 is then directed toward the Bourdon tubes of the pressure control apparatuses l8, l9 and 20, by means of the respective tubes 21, 22 and 23.

The basic diagram of these conventional controls is given in FIG. 3. In this Figure, the tube that supplies the Bourdon tube 24 has been numbered 25. According to the pressure of the fluid contained in 25, the Bourdon tube 24 displaces, more or less, the vane 26 in front of the opening 57 of a chamber 59 by means of mechanical connection 27. Chamber 59 is supplied with a fluid coming from conduit 28 and going through chambers 56 and 59 which are separated by a calibrated opening 58. The pressure prevailing in chamber 56 is the feed pressure, whereas the pressure in downstream chamber 59 is a function of the interval between the vane and the opening 57, that is to say, the pressure prevailing in the Bourdon tube, connected to tube 25. In the example shown in FIG. 2, tube 25 of FIG. 3 corresponds to tube 21 and tubes 28 and 29 in FIG. 2 correspond, respectively, to tubes 30 and 31 in FIG. 2.

Such instruments are sold conventionally for operation with an opening 57 leading into an environment where atmospheric pressure prevails. The present invention has modified this apparatus so that it will work in an environment where a predetermined pressure exists that is greater than the strongest pressure of the surrounding environment into which the capsule is to be immersed and the apparatus of the invention maintains the pressure prevailing in the casing at the level of this predetermined pressure.

In order to control the various controls, the invention utilizes the gas coming from desiccator l5, reducing it in reducervalve 33. The reduction thus brought about entails a certain cooling and a new condensation of the water which is eliminated by means of condensation pot 32 and conduit 34. Normal temperature is restored by channelling the gas toward a second heat exchanger 35, similar to exchanger 13. This reheating is important since it enables the apparatus to eliminate any trace of condensation and, consequently, any risk of attack upon the instruments by the sulphuretted hydrogen which is contained in strong doses of the gas.

Conduit 36 is connected through a regulating reducer 37 to tube 30 which in turn is used to feed the control apparatus 18. As mentioned earlier, the pressure collected at 31 is a function of the pressure prevailing in tube 21. It then becomes possible to regulate the flow rate of conduit 6 by means of a conventional device such as 38, receiving on the one hand, the controlled pressure prevailing at 31 and on the other hand, a fixed, determined pressure prevailing in tube 39 which is connected to conduit 36 through regulating reducer 40. Device 38 controls the movement of the valve shown schematically in 41 through the control connection 42.

Conduit 39 is connected to valve 43, one of whose openings leads into the interior of the capsule so as to produce initially the predetermined pressure which is higher than the hydrostatic pressure to which the casing on the capsule is subjected.

In this way we can use the commercially available, previously regulated apparatuses for operation under these pressure conditions.

Apparatus 18 has an evacuation opening 57 which is controlled by the vane of the Bourdon tube; this apparatus 18 releases a certain quantity of fluid tending to increase the pressure inside the casing; this is the reason that valve 44 is provided so as to expel any surplus of gas thus introduced into the interior of the casings; this valve is directly connected to the outside by conduit 45.

Apparatuses l9 and are differential apparatuses of a type similar to the one shown at 18. They involve a second Bourdon tube, supplied by conduits such as 47 as shown in FIG. 4 and connected to conduit 7 by means of valve 48. The evacuation opening 57' is controlled by the differential between the two Bourdon tubes 24' and 61. Thus, the pressure prevailing in chambers 56 and 59 is controlled by the vane 26'. A mechanical link 62 connects the Bourdon tube 61 with the vane 26' which pivots about point P. The pressure from line 17 via line 23 enters Bourdon tube 24' while the pressure downstream of reducing valve 53 enters the chamber via line 28'. One can thus automatically regulate, in the known manner, the valve 49 through which the crude comes in, by any mechanical device 50 which is controlled by the pressure furnished by outlet conduit 51 of apparatus 19. This pressure is a function of the pressure intervals prevailing in gas conduit 5 and oil conduit 7. Apparatus 19 is supplied in a manner similar to apparatus 18 through a regulating reducer 52 which is connected to conduit 36.

In a similar manner, apparatus 20, supplied by regulating reducer 53, enables us to control regulating valve 54 of conduit 8 by means of the pressure supplied at 55; this pressure is also a function of the pressure differences between the gas pressure and the fluid pressure.

Although in the above we have described only one way of building such an instrument capsule according to the invention, it is clear that various additions or substitutions could be made in various parts of the capsule without going beyond the framework of this invention.

It is clear that the invention could also be applied to all installations requiring the regulation of the flow rate of fluids circulating in various conduits whenever measurement and control instruments must be protected against an environment capable ofattacking them or capable of upsetting them due to the pressure variations in that environment.

What is claimed is:

1. Apparatus for the remote control of the flow rate of the products of an underwater oil well utilizing the flow energy of the products for regulation of the flow rates comprising;

a fluid-tight housing;

at least one fluid conduit passing through the housing carrying a gas fluid from the oil well;

means for removing a portion of the gas fluid having a first gas fluid pressure;

means for reducing the pressure of some of the gas fluid to provide some gas fluid at a second pressure;

comparison means for generating some gas fluid at a third control pressure as a function of the first and second gas fluid pressures including means for releasing some of the gas fluid into the fluid-tight housing to provide an internal pressure greater than the exterior hydrostatic pressure; and

valve means for regulating the flow of the gas fluid through the fluid conduit in response to the third control pressure.

2. Apparatus for the remote control of fluid flow rates utilizing the flow energy ofthe fluid for regulation, comprising;

a fluid-tight housing;

a fluid conduit passing through the fluid-tight housing;

means for removing a portion of the fluid having a first fluid pressure;

means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure, including a reducing valve, condensation means and a heat exchanger; comparison means for producing a signal as a function of the first and second fluid pressure;

means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means.

3. Apparatus as in claim 2 where the signal produced by the comparison means is a third control pressure.

4. Apparatus as in claim 2 where the comparison means includes a Bourdon tube.

5. Apparatus as in claim 4 where a portion of the fluid removed from the fluid conduit is released by the comparison means into the fluid-tight housing to raise the internal pressure above the environmental pressure surrounding the housing.

6. Apparatus as in claim 4 further including a heat exchanger mounted on the outside of the housing and a desiccator means mounted on the inside of the housing.

7. Apparatus as in claim 4 further including a pressure release valve for releasing excess internal pressure.

8. Apparatus for the remote control of fluid flow rates utilizing the flow energy of the fluid for regulation, comprising;

a fluid-tight housing;

a first fluid control passing through the fluid-tight housing;

means for removing a portion of the fluid having a first fluid pressure;

means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure;

first comparison means for producing a signal as a function of the first and second fluid pressure;

means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means;

a second fluid conduit passing through the fluid-tight housing;

means for removing a portion of the second fluid in the second conduit;

a second comparison means for producing a signal as a function of the first fluid pressure and the second fluid pressure, and

means for regulating the flow of the second fluid in the second conduit in response to the signal produced by the second comparison means.

9. Apparatus for the remote control of fluid flow rates utilizing the flow energy of the fluid for regulation, comprising:

a fluid-tight housing;

a fluid conduit passing through the fluid-tight housing;

means for removing a portion of the fluid having a first fluid pressure;

means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure;

comparison means for producing a signal as a function of the first and second fluid pressure;

means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means, and

means for releasing a portion of the fluid removed from the fluid conduit into the fluid-tight housing to raise the internal pressure above the environmental pressure surround ing the housing. 

1. Apparatus for the remote control of the flow rate of the products of an underwater oil well utilizing the flow energy of the products for regulation of the flow rates comprising; a fluid-tight housing; at least one fluid conduit passing through the housing carrying a gas fluid from the oil well; means for removing a portion of the gas fluid havIng a first gas fluid pressure; means for reducing the pressure of some of the gas fluid to provide some gas fluid at a second pressure; comparison means for generating some gas fluid at a third control pressure as a function of the first and second gas fluid pressures including means for releasing some of the gas fluid into the fluid-tight housing to provide an internal pressure greater than the exterior hydrostatic pressure; and valve means for regulating the flow of the gas fluid through the fluid conduit in response to the third control pressure.
 2. Apparatus for the remote control of fluid flow rates utilizing the flow energy of the fluid for regulation, comprising; a fluid-tight housing; a fluid conduit passing through the fluid-tight housing; means for removing a portion of the fluid having a first fluid pressure; means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure, including a reducing valve, condensation means and a heat exchanger; comparison means for producing a signal as a function of the first and second fluid pressure; means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means.
 3. Apparatus as in claim 2 where the signal produced by the comparison means is a third control pressure.
 4. Apparatus as in claim 2 where the comparison means includes a Bourdon tube.
 5. Apparatus as in claim 4 where a portion of the fluid removed from the fluid conduit is released by the comparison means into the fluid-tight housing to raise the internal pressure above the environmental pressure surrounding the housing.
 6. Apparatus as in claim 4 further including a heat exchanger mounted on the outside of the housing and a desiccator means mounted on the inside of the housing.
 7. Apparatus as in claim 4 further including a pressure release valve for releasing excess internal pressure.
 8. Apparatus for the remote control of fluid flow rates utilizing the flow energy of the fluid for regulation, comprising; a fluid-tight housing; a first fluid control passing through the fluid-tight housing; means for removing a portion of the fluid having a first fluid pressure; means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure; first comparison means for producing a signal as a function of the first and second fluid pressure; means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means; a second fluid conduit passing through the fluid-tight housing; means for removing a portion of the second fluid in the second conduit; a second comparison means for producing a signal as a function of the first fluid pressure and the second fluid pressure, and means for regulating the flow of the second fluid in the second conduit in response to the signal produced by the second comparison means.
 9. Apparatus for the remote control of fluid flow rates utilizing the flow energy of the fluid for regulation, comprising: a fluid-tight housing; a fluid conduit passing through the fluid-tight housing; means for removing a portion of the fluid having a first fluid pressure; means for reducing the pressure of some of the removed fluid to provide fluid at a second fluid pressure; comparison means for producing a signal as a function of the first and second fluid pressure; means for regulating the flow of the fluid through the fluid conduit in response to the signal produced by the comparison means, and means for releasing a portion of the fluid removed from the fluid conduit into the fluid-tight housing to raise the internal pressure above the environmental pressure surrounding the housing. 